steps

Place a pot of water on to boil for macaroni. Heat a sauté pan over medium high heat. Add oil and chicken and season with salt and pepper. Sauté a couple of minutes then add onion and cook for about 5 - 7 minutes until onions are tender and chicken is cooked through. Turn off heat and reserve.

To boiling pasta water, add pasta and salt to season the cooking water. Cook for 5 minutes, then add broccoli and cook for 3 minutes more or until pasta is cooked to al dente and florets are just tender.

While pasta cooks, heat a saucepan over medium heat. Add butter and melt, then add flour, cayenne and paprika and whisk together over medium heat until roux bubbles then cook 1 minute more. Whisk in milk and stock and raise heat a little to bring sauce to a quick boil. Simmer sauce to thicken about 5 minutes.

Drain pasta and broccoli florets. Add back to pot and add chicken to the pasta and broccoli florets. Add cheese to milk sauce and stir to melt it in, about a minute. Stir in mustard and season sauce with salt and pepper. Pour sauce over chicken, broccoli and cooked pasta and stir to combine. Adjust seasonings, transfer to a serving platter. Serve.